Sound printing mechanism



Feb. 6, 1951 J. A. DREYFUS 2,540,560

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soUND PRINTNG MECHANISM Filed Dec. 29, 1948 I 11 sheets-sheet 11 M10v La/L 139 INVENTOR: Jean Alberi DrEj/us ATTO (LN E55 latenteci Feb. 6, l95l SOUND PRINTNG MECHANISM Jean Albert Dreyfus, Geneva, Switzerland Application December 29, 1948, Serial No. 67,900 In Switzerland January 8, 1948 2s claims. 4(o1. irs-31 Various forms of electro-acoustic apparatus are known which break up the spectra of frequencies of microphonic oscillations into partial v nish indications of the energy components of sounds as a function of the frequency (spectrographs) or they may, in certain special conditions, operate relays as a function of the fixed energy components of certain sounds.

The known devices are not adapted to transform, for example, phonetic or phoneme (speech) elements (such as vowels and consonants) into graphic elements, such as alphabetic or codiable symbols.

In effect, each sound in general and each phoneme in particular is a train of acoustic waves (a series of sinusoidal waves according to Fouriers theorem) which the hearing transforms into a sound image (a series of nervous impulses).

Physically the sound is presented at one time as a wave phenomenon in the air, at another time as a mechanical or corpuscular phenomenon in nerve bres.

The apparatus according to the invention reproduces electro-mechanically certain physiological functions of the ear, of the nervous system, of the brain and of the muscles. It decomposes the frequency spectra of a microphonic oscillation (excited by a sound) into a number 1L of partial oscillations with the aid of n acoustic band filters, the mean frequencies of which are the relative band widths Qnz'nznf'n oi which are of the same order of magnitude as of the relative band widths Qln of the resonators of the sound emitter. These partial oscillations are transformed into energy variations with the aid of rectifier circuits followed by low-pass lilters, the time constants Tn of which are of the same order of magnitude as the time constants T111 of the transient parts of the emitted sound. Thereafter the diiierential effects of these energy variations are transformed into electrical impulses, of which certain combinations may operate two-dimensional oscillographs or relays.

' In a general manner, the apparatus, according to the invention, can be called a sonograph freni the Latin sonus equals sound and from the Greek graph equals the action of writing. It permits certain types of sounds to be transformed into certain graphic types or into characteristic tele-controls or signals. the sound type is that of phonemes the appara- When tus may be called a phonetic sonograph. When the apparatus comprises a two-dimensional oscillograph it can be called a stenosonograp When it comprises a typographical typewriter it can be called a typo-sonograph.

The graphic products of the sonograph may be called sonograms The method may be described as Sonographie The electrical impulses may be transmitted to a distance by wire or by electro-magnetic Waves, While the apparatus according to the invention can transmit telegrams orally (teleor radio-sonograms).

Figures 1 to 43 illustrate, by way of example, certain constructions according to the invention.

Figure l represents the spectra of the transient frequencies of the main phonetic elements or French phonemes. They permit the relative emitted band widths Qin to be deduced for a phonetic sonograph;

Figure 2 is a diagram showing the principle of a phonetic Steno-Sonograph with six components;

Figure 3 shows the pass bands corresponding to Figure 2;

Figure 4 is a diagram showing the principle of a theoretical typo-sonograph with four components;

Figure 5 is an electrical diagram of a sonograph with seven components, the bands of which are indicated by Figure 6;

Figures '7 and 8 show in elevation and section a transformer for a band lter;

Figure 9 is a section of an electro-dynamic relay;

Figure 10 is a table of combinations for a phonetic ty-po-sonograph with seven components, the bands of which are indicated in Figure 11;

Figure l2 is an electrical diagram of a typosonograph limited to the differentiation of five vowels;

Figure 13 indicates the corresponding current oscillations and variations;

Figure 14 shows the frequency bands;

Figure 15 is a table of combinations;

Figure 16 shows the characteristics of an electronic tube corresponding to Figure 12;

Figures 17 and 18 show modifications of the relays of Figure 12;

Figures 19 to 22 show tables of combinations using a part of the frequency bands of Figure 14, being limited to the diiierentiation of three vowels;

Figure 23 shows five frequency bands permitting six or eight vowels to be differentiated according to the combination tables of Figures 24 and 25;

Figure 26 indicates seven bands of frequencies;

Figure 27 shows the star connection of the corresponding steno-sonographic coils;

Figure 28 shows the star connection of eight components;

Figure 29 shows several practical values corresponding to the diagrams such as that of Figure Figure 30 indicates 5 bands of frequencies;

Figures 3l 4and 32 show simplified diagrams for the differentiation of a limited number of vowels pronounced separately;

Figures 33 and 34 show four components;

Figures 35 to 38 show phonetic stenofsonograms with two and with four components;

Figures 39 to 43 show in elevation and in` section an improved two-dimensionalscillograph adapted to work with a steno-sonograph withsx components. Figure 1 shows the acoustic frequency'spectra `ofthe initial transient part offwave trains constituting the main phonetic elementsor phenomes of the French language. It will be notedthat for frequencies between L19@ and 4,000 cycles'per second, the relative band width ,Q1 of the sounds emitted increases approximately between 1*.'5 and 3. See also a publication ofthe authorin 'the Helvetica Physica Acta, volume XIX, Faso. 6-'7 (1946), entitled On the transienty spectra of phonetic elements (Sonographie analysis) according to the report of communications to the Meeting of the Swiss Physical Society of the 8th September 1948 in Zurich.

On the other hand, the band of J90 to 390 cycles per second can hardly be subdivided, Ibecause the pitch of the voice of theV speaker canvary normally between these limits, in such a manner that the width of the relative band maybe fn: (390+90) :2:240, andnfn=39090=300 cycles per second. rilhere still exists a band comprised between 40 and 80 cycles persecond which can help to characterize the stopped consonants such as l; and p. Experimental researches `ofthe authorhave shown that the characteristic border lines between ou and o, o and a, a and im, un and u, u and i, are found near 389, 720, 1260, 1750 and 256() cycles per second.

In consequence, the transient phonetic f requency spectra may be broken up into eight frequency bands, of which the mean frequencies f1 and the border line frequencies fn, n+1 are as follows:

sionally other bands in the cases of simpliiied breaking up.

Figure 2 shows a diagram of the principle of a phonetic steno-sonograph with six components,

the frequency bands of which are indicated by Figure 3.

The train of acoustic waves V1 constituting, for example, the sound of the vowel e, is transformed into a microphonic oscillation V2 .by means `of a Vconstants of these circuits are selected in such a manner that the variations of the rcctied current reproduce the envelope of the transient parts vof the wave train. Thus, these time constants may, in the phonetic case, be of the order of 5 Amilli-seconds which would permit of the elimination of acoustic frequencies higher than 100 cycycles per second and the selection of the transient Variations.

`Each variation of rectified current thus presents an initial transient part and a final tran- .sient part between which there is sometimes found (in long vowels) a quasi-stationary part.

the rectiiied currents.

These variations of rectified current V41 to V40 are transformed into six initial impulses V521 to `V520 with the aid of cii cuits which. diflerentiate between. increasing and decreasing variations of These circuits maycomprise coupling condensers and oppositely-connected ,rectiiiers the initial impulses being Vpositive and the` final impulses negative, for example. The six initial impulses V511 to V510 pass through the six star-connected coils B1 to Bs, of a twodimensional oscillograp-h and their resultants have for combined differential effect to cause a scriber to describe a graph C1-0 which is recordedby a sheet of paper, this latter being, for example, given a translatory rmovement Mp.

This graph or sonogram can serve Aeither Vas a differential spectrogram, utilising polar coordinates or it can act as a codilable or alphabetic symbol.

The resultant Vs of the nal impulses, such as vV521 to V526 may serve to restore to zero the micror. phonic oscillation V2 in the amplifier, so as to render the following wave train independent of the preceding one. This can be eiected with the aid of a release oscillator which supplies a very .brief negative impulse (of a few milliseconds) to the grid of an amplifier valve, each time it receives a final resultant V0.

Figure 4 is a diagram showing the principle of a theoretical phonetic typo-sonograph with n=4 components. The generator of the initial andfnal impulses is similar to that of Figure 2, but the two dimensional oscillograph is replaced Vby a relay combiner and integrator. The 11 initial impulses, such as V511 to V514 can be diiferentiated .two at a timeup to a maximum number of such as |1l2 to 6162. A typewriter key may De released by an impulse relay such as IM2- each time a number S of series-connected contacts, such as two contacts he and 421 are closed simul- .Such as l.taneously by as many different differential relays,

such as |112 and 4142.

-The maximum number A of impulse relays which can be released by the aid of D differential relays and S contacts in series is Aaa-2s such as On the other hand, the table below indicates maximum numbers A of impulse relays (or of typographie keys) as a, function of different numbers D of differential relays and numbers S of contacts in series:

These figures obviously only have significance in so far as theoretical limit values are concerned.

All the combinations of differential relays and of contacts in series are not practicable. It is necessary on the contrary to select the corresponding combination, for each phoneme, in accordance with the formants or characteristic frequency bands of the latter. This condition restricts considerably the practicable combinations as will be described later.

Figure shows the electrical circuit of a sonograph with n=7 components the frequency bands of which are shown in Figure 6.

The microphonic oscillation furnished by the microphone M1 is amplified by the valves E1, E2. The anode circuit of E2 comprises a series of 7 band lters n=1 to n=7 which break up the microphonic oscillation into 'l partial oscillations such as Oi. The latter comprises a transient part of duration t1, a final transient part of duration t3 and sometimes a quasi-stationary part of duration t2. The durations t1 of phonemes are usually of the order of 5 to 50 milliseconds. The duration t2 may vary between 0 ms. for the stopped consonants and several seconds for the very long vowels.

Each band filter comprises a transformer with two separate inductive windings Lni and Lnz which are tuned by the condensers Cm and Cuz. Variable resistances R111 and Rm allow the damping coefficient to be adjusted. The coupling between Lni and Luz is variable.

The secondary of each tuned transformer is connected with two full-wave rectifier circuits, comprising the resistances Rna, Rar, the condensers Cna, Cnr and the rectiiers (such as crystal diodes) Gm, Gnz.

Each rectifier circuit is followed by a low-pass filter with the resistances Rus, Rae and the condensers C115, Cna. The time constants Rn-CnL-Tn of these circuits are comprised between about 2 and 50 ms. T1 can be made equal to 5 ms. for the stopped consonants, and T2 to T7 can be between and 20 ms. for the other phonemes.

Thus the partial oscillations. such as Oi, are

6 transformed into variations of two opposite rectified currents (or partial energy variations), such as O2 and O3, the positive and negative potentials of which appear at the terminals of the resistances R115 and Ras.

The coupling condensers Cm, Cna, Cas selectthe transient parts (increasing and decreasing) of these variations and these appear as transient impulses (initial and final) O4 to O7 at the terminals of the resistances Rulo to Ruiz, which latter are shunted by the condensers Cnr@ to Cniz and form other cells of low pass filters. Thus,` the quasi-stationary parts of the variations of rectified current are eliminated.

The rectifier Gag and the variable resistance Ruis select the initial positive impulse O4 which becomes Os, while eliminating O5. The rectier Gai acting in the opposite direction, selects the final negative impulse O5, which becomes O9, while eliminating O4. The rectifier Gus selects the initial negative impulse Os, which becomes Om, while eliminating the final positive impulse O1.

The initial positive impulses Os, filtered by the condensers Cms, Cms are amplified by valves Eni, the anode currents of which are practically zero in the absence of impulses (class C), and they pass through the differential magneto-motive coils B11 to B71, which, may for example, be those of two dimensional oscillograplis or of the differential relays indicated in Figures 2 and 4. The latter are selective of the duration of the impulses, acting either as mechanical resonators for a sub-acoustic frequency of between about 20 and 10 cycles, or for sub-acoustic frequencies included between and 5 cycles per second, which are selected by electrical filters associated with these relays. It is thus possible economically to differentiate plosive phonemes, for example. A suitable resultant of the final negative impulses O9 may serve to release a brief negative impulse (2 to 10 ms.) with the aid of an oscillator E4, thus stopping the microphonic oscillation, by acting on the grid of the valve E2.

' This allows the syllables to be broken up into phonemes.

A suitable resultant of the initial negative impulses Oin may either serve to compensate for the undesirable variations of intensity of the wave trains or to repeat the impulses in the case of quasi-stationary parts exceeding a certain duration. That resultant may act on the grid of the valve E1 by the intermediary of an electronic valve device E5. The devices Er and E5 may be similar to those which are known either for relaxation oscillators or for automatic voi urne control.

Figures '7 and 8 indicate diagrammatically in elevation and in section a transformer adapted to be used with the band filters n=1 to uz'l. The primary and secondary windings l and 2 are wound on bundles of sheet metal 3 and 4 which are arranged symmetrically on opposite sides of an air gap the width of which is variable in such amanner as to vary the coupling coefficient between, for example, 0.98 and 0.2. Thus, the width of the band passed'can be adjusted within very'wide limits.

Figure 9 is a diagrammatic sectional view of j anl electro-dynamic differential relay which can comprise two windings such as B11, B21 (Figure 5). These windings are wound in aLmovablecoil 8,- which-is suspended in'the air gapof a permarnentanagnet Q-by a system of bladespringssuch fully. The-time of response of these relays may be varied between 6.1 and severalmilli-seconds. Condensers Gr.15, C1116 may serve either to cornpensate `for or to produce relative phase displacements betweenthe impulses.

Figures-l and ll give a table of combinations of a phonetic typo-sonograph with '7 components 11:0 to n=6, which comprises 16 differential relays Doi to D55 and 32- typographical keys corresponding to these phonemes, each of-these keys being Yadapted to be released by the series of 3 to 4 contacts. For example, the contact will be released by the simultaneous closing yof 3,0011- tacts 2 l, iifopcrated by the 3 differential relays D12, D13, D34. (The inversion of the numbers of a diiferential relay indicates the inversion of the closing of the latter.)

Thus, out of the maximum numberD=2l :of the possible differential relays for 7 components, it is possible to choose only 1 6, and out of the maximum possible number A, which is more than 2.000, of operating relays only 32 are required.

Figures 12 to 35 indicate the electrical diagrams and the frequency bands of phonetic typo-sonographs which are restricted to be controlled by certain vowels (sonographs cf vowels) to the number of or 3 or 6 or 8.

According `to Figure l2, the oscillation supplied by the microphone 2l isV amplified by a compensated `amplifier 2:?, then broken. up into 4 partial oscillations, such as V11, V12 `in Figure 13, with the aid of Il band filters 11:1 to 1L=4, the pass bands of. which are indicated in Figure 14. Circuits comprising the rectiors G11 to G14, the resistances-R41 to R44 and the condensers C41 to C44 and the low-pass ffl formed by the resistances R51 to R54 shunteci oy the condenser-s C51 to C54, provide 4 variations of the rectified current, such as V21, V22. The lair-.1erl are transformed into initial and final impulsessuch` as V31, V41 and V32, V42 by the coupling condensers C51 to C54 and the variable resistances R71 to R54. The rectifier valves G21 to G24, the characteristics of which are indicated on Figure i6, select-and amplify the initial impulses such as V51, V52. The three diierential relays D12, D22, D34 respond to differences in the impulses arising from successive components arranged in the order of the frequency bands. Each vowel circuit such ,as Ou, O, A, E, I is closed when two contacts in series arranged on two different dierential-relays are closed simultaneously under theeiect of the corresponding vowelpronounced in. front of the microphone El. The directional combinations of the differential relays .are indicated in Figure l5.

The time constants of the circuitsdescribed may be selectedbetween 2) and 1G() milli-seconds. For large time constants a spoken word will only act through the vowel which it contains. It will, for example, makeV no difference whethervthe .,Avimgqels.,. E,A O, LA,A are pronounced or, theA word Veronica According to Figure 17, each double-wound differential polarisedrelay," such as D12, may be replaced by simple two-winding relays.

According to Figure 18, each differential twowinding relay can be replaced by a polarised. relay having,,a,single.winding by making use of bridge circuits comprising rectiers such as G15, G16, G25, G26.

FigureslQ to 22 indicatetablesof combinationspf,diielfentialfimpulses. similarto those of Figures Y12 and 1 5butsimplied so as only to respond to 3 vowels, such'as OU, A, I or O, A, E,

-or;OU, O, I. Tothissenditfmay be suiiicient to ;:prQl/Qdegthreef,filter bands, such as 12:1, 3, 4 or 2,

3 ,.4,- and two differential relays,- such as D13, D34 (OU, A, I) Or D23, D34 (O, A, E), to v1dlerelllate different vowels.

Figure23 indicatesfive pass bands and Figure 24 showsY the corresponding combinations of three l,diiierential.relays l312, D22, D45, allowingthe six ,vowels QU, O, A,U, E, l.` tobe `diilenentiated with the ,aidof V a series'of two contacts.

, Figure,-25 .ir1dcatesjthe combination of four differential relays which, withthe` aid of the vc passV bands in Figure 23 and a series of three contacts,y permitof lthe eight vowels OU, A, I being differentiated.

-1Figures=261andf27 indicate the seven pass bands and the cross-connection o1' seven two dimensional roscillograph.magneto-motive coils which .permit'xof the `.provision :of a phonetic steno- -sonograph having seven components, as well as certaingraphic categories adapted to be pro- The printer fmaybe ink, electro-chemical, thermo- =electricor it may operate according to any other `methodfofy direct inscription. t may also be replaced by acmethocl Aoi photographic inscription using a special cathode ray oscillograph having seven components.

HIn-flike manner, Figure 28 shows the arrangement in an octagonal star form lof a phonetic steno-sonograph with eight components.

-Figure 29 indicates several practical values corresponding to the'electrical diagram of Figure 5. fFigure 31 showsan electro-acousticdevice similar to thatof Figure25, but limited to the use of vowels'or long consonants pronounced separately, with intermediate silences.v In these conditions, the apparatus may be Ysimplified and electronic valves may be omitted. It may be called a sonograph for `spelt vowels. It comprises 5 filter bandsthe resonance curvesrof which are indicated in Figure 30.. Condu ctive couplings may be providedusing variable resistances R415, or use maybe made of .capacitative couplings with a higlrtime constant ms.). In spite of the simplicity` ofthe apparatus, there can` .be differentiated, under particular conditions of pronunciation, vowels suc has-OU, C, A,.1I-, EU, U, I usingonlyfiive differential relays D12 to D51. The variationsotthe,rectiedcurrent V112 are not differentiateddn time,.but only in space. Phase displacernents4 .between two .differentiated .variations such as Vus, V414 the diierence of which is V114 may be` compensated for by the use of condensers C115 giving Vus as .thedifference- VInorder to obtain a greater control energy, but

for a more limited number of spelt vowels, the circuit-fof Figure,v 32 .canbe utilised, this comprising -four filters, .thebands of which are indicated in fFigure'fBSpand four differential relays D12 to D41. Thus, a partial oscillation such as Wm, is transformed into Wnz, then into Wna and WM by means of rectifying and amplifying electronic valves Gua. The phase differences Wns (or Wn'z when synchronized with the aid of condensers Cns, Cna) between two impulses WM, Wns operates a differential relay such as D12.

The four iilters the bands of which are indicated by Figure 33 may operate a two-dimensional oscillograph having four cross-connected components to 4 as shown in Figure 34. The movement of the paper is effected in the direction of the bisecting line 5. The components are differentiated in time with the aid of a circuit similar to that of Figure 5.

For the registration of sounds other than specifically phonetic sounds, there can be used a number n of band lters which is other than those indicated. For example, there may be utilized mean frequencies fn. the ratio of two successive mean frequencies being a constant ratio and the relative width of the band Qn being The ratio K may be chosen eoual to a fraction of a whole number such as 5/3=1.665.=a large sixth, 8/5=1.6=a small sixth, 3/2=l.5=a fifth, 4/3=1.33='ouarter. 5/4=1.25=a third. or nally 16/15=1.065 a major semi-tone. It is thus possible to reproduce the characters of musical or other sounds. In a general manner. the width of the relative band Qn of the Sonographie receiver will be of the same order of size as that Q1 of the sound emitter.

It is possible tn eliminate the phonemeoffraphic and detector eiect, for example, the pitch of voice or the emotion of a sneaker using a stenosonogranh with four cross-connected components, the iour frenuencv bands being comprised between 100 and 400 cvcles per second.

A universal sonoeraph mav be constructed permitting the components in the frequencies to be varied both as regards their time constants and their combinations utilising a mulitple commutator.

Figures 35 to 38 show several phonemeograms recorded with the aid of a steno-sonograph having four cross-connected components as shown in Figures 33, 34. Figure 35 gives vthe differential spectrograms resulting from two diametral components |3 and 2 4. Figure 36 shows phonemeograms with four phoneme components to A repeated four times with the voice pitch varied between 100 and 250 cycles per second. Figure 37 shows a kind of Steno-Sonographie alphabet. which is one out of an unlimited number of possibilities. Figure 38 reproduces several syllables.

Figures 39 to 43 indicate the improved mechanical construction of a steno-sonograph with six components corresponding to a part of Figure 2, the needle being suspended by a resilient ball and socket joint and the paper being automatically replaced.

The apparatus comprises a certain number n of pairs of electro-dynamic motors, such as |0| and |02, |03 and |04, |05 and |05 arranged regularly in star form around the shaft |01 of the recording index |08. The number n may be 2, 3, 4, 5 etc. Each pair comprises two motors, such 10y as |0| and |02, which are diametrically opposed. The angle included between the axes are 360:2n. In the present construction, there are three pairs of motors, that is to say, six motors in all, and the angles are 60.

Each motor, such as Mil, comprises a movable coil |09 suspended by a spring system such as I0, in the air gap of a permanent magnet ||2. Each movable coil comprises two windings such as ||3, H4. When a winding H3 is traversed by an electric current oscillation, oi an acoustic or sub-acoustic frequency, the coil |09 executes translatory vibrations of an amplitude a. These vibrations are transmitted to the index |08 by means of rigid rods ||5 and flexible steel wires H6, ||1 forming ball-joints which are free of play or wear. The needle is suspended by a system of curved blade springs H0 to |20 which constitute a resilient axial bearing. This ball joint keeps the point of rotation |2| of the needle |08 in the axis |01, while permitting the point of rotation |2| to be moved resiliently along this axis. Thus, the translatory vibrations of the coils, such as |09, are transformed into ampliiied vibrations of the point of the needle |08 which may follow a curve of the recording paper |22, while exerting a certain pressure on the latter.

The blade springs supporting the needle are situated. when at rest, in a plane normal to the axis of the needle. Each blade may comprise a certain number of sectors and annular segments.

The suspension of the movable coil |09 may comprise two parallel systems |0l. consisting of blade springs similar to i l0 to |20.l The blades may be arrangedA regularly in star form, to the The needle |08 may be hollow and serve as-an ink channel. the ink being conducted from thev reservoir |21 by the flexible tube |23. The point of rotation 2| being in the neighbourhood of the connection between the needle |08 and the flexible tube |28. the latter does not interfere with the movements of the needle. The needle may contain a flexible metallic wire closing or opening the .point of the vibrating needle automatically.

The recording paper |3| may be of rectangular form and is wrapped round the rigid cylinder |33. This cylinder may be driven-with a rotary movement, which is communicated to it frictionally by the driving wheel |34, and with a translatory movement communicated to it by the wheel |35 which is engaged in a helical groove |35 in the rigid shaft |31. Considered in relation to the point of theneedle |08 when at rest, the projection of the needle describes a helical line on the paper. When the sheet of paper |22 is opened out this line is presented in the form of a succession of inclined and parallel lines such |-2, 2-3 5-6, in Figure 43.

A device may be provided for automatically replacing the sheet ot' paper, thus permitting uninterrupted recording over a period lasting several'te'ns of horsfthe' recordingv being Vstarted as the length of the sheet of paper 13|: andthe width of which is a fraction'of a millimetra A roll of paper |39 adapted' to' furnish the'material for several hundreds or thousands 'of sheets of paper is arranged in the interiorof the cylinder |332' The end of the paper |22 passes out through the slot |38','makes a complete turn around the cylinder |33, re-enters` through the same slot,` passes around two pairs ofV driving rollers |40 to |43"and Vagain makes a complete turninthe space between thecylinder |33 and the paperroller |39. Aknife |44operated by the fca'rfn* |f|5 cuts' the paperV andfrees the Vend |46 after recording. s

rThe automaticreplacement operation isv asV follows. The needlevv |08 haring covered the graph sheet or section 122,111@ toothed wheel mi or "i lll1` engages'fagainst a toothed driyingwheel 8orl |481. `TheA rollers lsltililto |43 "cause the` paper to advancemthrugh a distance correspon'dingto the widthofa "section'in a direction opl posite 'to he; latterfwhich is lcommunicated to the `peri'pl'iery Lof the cylinder"|33 bya/driving WheelA |34L' Simultaneously, af'commfutator reverse the electric: supply :tothel electro-dynamic motors` |U| rvto` |06; Thereafter, thesection of the lpaper is replaced by the following section, theidirection of` rotation of the driving wheel |34s reye'rsed and the cylinder returns in the reyersefdirectionto its starting position. The` inscription ofthe rst section is made on the lines I z to -.6 of the sheet ist. That of the" following section laccording toy Hthevire'verse" lines 6-1 to-|0| of the sheet |32,v Theinscription ofreachnrs't line of a/sheet |3| or |32 is effected while the 'cylinder' |33has` stopped and the paper is moving relatively to the cylinder` and to the point `f the needle at a speed equal to the peripheralmspeed of the `cylinder.

possible to make fuse of'A differences between the peripheralspeeds'of the cylinderI of the paper.

As 1a' result,` anl interrupted're'cording is obtained on'a succession 4of standard sheets of paper, the knife |44 automatically liberating` the iin'- ished sheet, which canine drawn backthrough the circular opening '|549 jformed in the Walls 5U, |5|J of the cylinder`|33.

In order to replace the paper` roller |39 vthe screws-|542, ljmayl'be loosened so thatjthe sup pori-{fwd} |55 can bepivoted around the shafts I, |51, thus enabling lall the cylinder'l and itsI 'contents to be withdrawn complete.

BladeY springs'such'as ||`8 to"|2'0 may' include" parts constituted by slotted#annularfseglnents. This'perm'itsthe opposing forceV of the spring to be lregulate'dby sliding the screws'in the slots. l

The mechanical characteristics' of the oscillograph may be such that it faithfully reproduces the subac'oustcfrequencies included between about 5 and 50 cycles per second. This may be doneby selecting ltheniornentl of inertia of the massesiassociated withfthe needle |88 and the degree of velasticity'of the springsmllli I in such a manner that the mechanical resonance of the-oscillograph is above 50 cycles per second. This mechanical resonance may be neutralised with the aid of anti-resonance 'electric' filters.

The above mechanicalconditions are easy to fulll because the o soillograph normally reproduces sub-acoustic frequencies. y

In a general manner,`A the deviceaccoiding to It would also be ouate.

"'numberof partial'osci-llations; rectier c" 12 the vinvention,whichis'called a Sonograph, is essentially an apparatusfwhich transforms the acousticfrequencies of 'a `sound into groups of impulses', of'sub-acoustic frequencies, correspond- 'ingto'transient parts of the sound. When, the

meanofl the acousticfrequencies of a phoneme is situated around"2,500fcycles per second, the corresponding' Sonographie frequency is about 25 lcycles per second, or Iv times smaller. Thus,

the movement ofthe recording paper of a stenosonograph maybe'effected at a reduced speed some'vihere between`5 and 1 cin/sec., on the aver age." Moreover, 'anelectric printing machine capable of ei'ct'ingy 25 strokes per second is ade- The feeding of the paper and the operation'ofth printerimay be controlled by difforential"impulses'.` The-advance of the paper may tliu's be'eiie'cted betveen thetimes of recording.

I claim? l. Inan elect'racstic apparatus for tran# forming' successionslof sounds into successions of mechanical movements; in combination with microphone transforming siccessions of sounds into successions of electric microphonic oscillahaving valves for amplifying said electric microphonic oscillations, a number of band filters connected with said means breaking up each amplined electric'microphonic oscillation into 'the same connected with said 'band -ilters Aand cor l interconnected'f-rectiners, resistances` condensers, and transforming each partial oscilla :tion into -a rectifiedoscillationnand low-pass `iilters connected-with-sa-id rectifier 'circuits and havingv interconnected 'resistances and condens-r ers, and transforming rectified oscillations into current variations of infraacoustic frequencies while suppressingfacoustc frequencies; coupling condensers and resistances connected therewith, said coupling-condensers producingr at thel terminals of thelast-mentioned resistances increasing electric impulses and decreasing electric ii pulses opposed to said increasing electric impulses "While suppressing quasi-stationary parts of the vibrations, other rectiercircuits connected wit the last-mentionedresistances and compri interconnected frectiers, variable resistances and condensers, coils connected with said other rectiner circuits and1eceiving increasing electric impulses therefrom, said coils transforming said increasing electric impulses -into mechanical. impulse componentsand yetother-rectiner circuits connected in parallel with said other rectifier-circuits and the grid of one of amplifyL ing valves and comprising interconnected rectifiers', variable vresistances and condensers, and receiving"decreasingelectric impulses and controlling'thereby the negative polarization of the grid of said'one amplifying valve.

2. Anelectro-acoustic apparatus in accordance with claim 1, comprising further rectifier circuits connected to said band filters in parallel to the rst-mentioed'rectier circuits and comprising' interconnected rectiers,r resistances and condensersQand transforming oscillations into curn rent variations opposed to said rectified oscillations, and other rectifying means` connected with said further rectier circuits andthe grid of the other one of said amplifying valves and comprising interconnected couplingcondensers, rectiers and variableres'istances, and transforming said current "Variations into increasing electriciapulses controlling the ^grid polarization ofsaid other 'amplifyingyah/e'.A

3. An electro-acoustic apparatus in accordance with claim A1, comprising an auto-oscillator interposed between the last-mentioned rectifier circuits and the grid of said one amplifying valve, said decreasing electrical impulses commanding the rhythm of oscillations of said auto-oscillator.

4. An electro-acoustic apparatus in accordance with claim 1, wherein a separate pair of coils receives each increasing electric impulse, said increasing electric impulses being transformed into mechanical impulse components by said coils, and a movable relay armature connected with said pair and being subjected to a differential effect of the resultant of said components.

5. An electro-acoustic apparatus in accordance with claim 1, wherein a separate pair of coils receives each increasing electric impulse, said increasing electric impulses being transformed into mechanical impulse components by said coils, and a movable oscillograph armature connected with said pair and being subjected to a differential effect of the resultant of said components.

6. An electro-acoustic apparatus in accordance with claim 1, comprising two relays and wherein said coils constitute a part of said relays, each of the two relays having two coils, and a plurality of pairs of contacts disposed in series, said relays having movable armatures actuating said contacts, and means connecting said coils with said other rectifier circuits so that each increasing y electric impulse will flow through two coils belonging to different relays.

7. An electro-acoustic apparatus inaccordance with claim 1, wherein the number of said band lters is equal to three, and comprising two differential relays having movable armatures, and means connecting said coils with said movable armatures, whereby said mechanical impulse components actuate said armatures.

8. An electro-acoustic apparatus in accordance with claim 1, wherein the number of said band filters is equal to four, and comprising three differential relays having movable armatures, and means connecting said coils with said movable armatures, whereby said mechanical impulse components actuate said armatures.

9. An electro-acoustic apparatus in accordance with claim l, wherein the number of said band iilters is equal to the number of said increasing electric impulses, and comprising differential relays having movable armatures, and means connecting said coils with said movable armatures, whereby said mechanical impulse components actuate said armatures, the number of said relays being selected from the number of combinations possible from one-half of the number of band filters.

10. An electro-acoustic apparatus in accordance with claim 1, wherein said coils produce mechanical impulse components the number of which is equal to 11, and comprising differential relays, the number of said differential relays being selected from possible combinations, contacts in series upon said differential relays, action relays, and means operatively connecting said contacts with said action relays, the number of said action relays being selected from possible combinations, wherein S is the num- Llo 14 ber of contacts in series for actuating an action relay.

11. An electro-acoustic apparatus in accordance with claim 1, wherein said coils consist of oscillograph coils having axes disposed in star formation, the number of said oscillographv coils being equal to that of said increasing electric impulses.

12. An electro-acoustic apparatus in accordance with claim 1, wherein said band lters comprise transformers having means constituting a variable air gap, sheet metal bundles disposed symmetrically on opposite sides of said air gap, and primary and secondary windings wound upon said bundles.

13. An electro-acoustic apparatus in accordance with claim l, comprising a magnet having an air gap formed therein, and comprising means movably suspending said coils in said air gap.

14. An electro-acoustic apparatus in accordance with claim 1, comprising an oscillograph needle connected with said coils, and an elastic support consisting of springs in star formation for suspending said needle.

15. An electro-acoustic apparatus in accordance with claim 1, comprising relays connected with said coil, and typographie keys operatively connected with said relays.

16. Electro-acoustical apparatus according to claim l, characterised by the fact that the n band-pass filters include at least three filters, the limits of which are selected approximately within the following limits: 40 and 80, 100 and 380, 60 and 640, 380 and 720, 730 and 1300, 640 and 1350, 1300 and 1800, 1800 and 2500, 1400 and 2500, 2500 and 3500, 3500 and 4600 cycles per second.

17. Apparatus according to claim 1, characterised by the fact that the band-pass filters number 4 and that they limit approximately the following frequencies; about 60, 640, 1340, 2440, 3640 cycles per second.

18. Apparatus accordingr to claim 1, characterised by the fact that the band-pass filters number 5 and that they Ylimit approximately the following frequencies; 60, 390, 730, 1350, 2450, 3800 cycles per second.

19. Apparatus according to claim l, characterised by the fact that the band-pass filters are of the number of 6 and that they limit the following approximate frequencies: 80, 380, 730, 1250, 1750, 2450, 3550 cycles per second.

20. Apparatus according to claim 1, characterised by the fact that the band-pass lters number 7 and that they limit approximately the fcllowing frequencies: 40, 80, 390, 720, 1300, 1800, 2500, 3600 cycles per second.

21. Apparatus according to claim 1, characterised by the fact that the band-pass filters number 8 and that they limit approximately the following frequencies: 40, 80, 380, 730, 1250, 1750, 2450, 3500, 4800 cycles per second.

22. Apparatus according to claim 1, characterised by the fact that the mean successive frequencies fn and fn+1, of two adjacent band-pass filters are in a constant ratio number greater than one, and that the width of the relative corresponding band is approximately 23. Apparatus according to claim 1, characterisedaby the/factthatthe ratio. of two successive meanwfrequencies of. twov adjacentband filters is selected from one of the following Values: sixth, fifth, `a quarter, third,` second,Y half-tone.

24.- Apparatus according -to claim 1, characterised by the fact that the time constants of the rectier ycircuitsand of the 10W-pass lters are betWeenZ and 15 ms.

25.- Apparatusaccording to claim l, characterised loy the. fact that the time constants of the rectier circuits and of the low-pass lters are between 5 and 50 ms.

26.Apparaus according to claim 1, characterised bythe fact. that the timeA constants of the 15 165; rectierr, circuitsandofatht10W-pass filters are betweenlO andi10 0ms.,.y

JEAN1ALBERT DREYFUS.

REFERENCES CITED The1fo11owng f referencesare of record in the file` of thisapatent;

UNITED 'STATES PATENTS 10 Number4 Name'` Date 1,801,657 Buyko Y Apr. 2l, 1931 1,951,454. Tefenbcher Mar. 30, 1934 2,137,888 Fu11erf NOV. 22, 1938 2,195,081 Dudley Mar. 26, 1940 

